Core drill bit binder materials

ABSTRACT

Ag-free or low-Ag binder alloys are provided that can be used as binders for abrasive materials such as core drill bits. The alloys comprise, or consist of, Cu, Sn and Ni, with Cu preferably the plurality or majority component. Methods of manufacturing abrasive materials comprising the binder alloys, such as infiltration processes, are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit under 35 U.S.C. § 119(e) of U.S.Provisional Application No. 63/257,725 filed Oct. 20, 2021, thedisclosure of which is expressly incorporated by reference herein in itsentirety.

FIELD OF THE INVENTION

The subject matter relates to materials that can be used as binders forabrasive materials such as core drill bits; to articles, such as coredrill bits, comprising the binder material; and to methods, such asinfiltration, for manufacturing such articles.

BACKGROUND OF THE INVENTION

Core drill bits are manufactured via an infiltration process whereby amold is packed with a matrix powder and infiltrated with a molten bindermaterial. The matrix typically consists of or comprises a particulatematerial such as tungsten although may comprise other materials such assilicon carbide. The binder material is typically a copper basedmaterial containing silver. Silver-containing binder materials areprevalent in core drill bits, despite the high cost of silver, due tothe good free cutting behavior of silver containing binders. There areknown copper based binder materials used by the drill bit industry (suchas oil drilling bits) more generally, Cu53 (Cu 53, Mn 25, Ni 15, Zn 7)which would be desirable from a cost perspective. However, these Ag-freealloys have thus far demonstrated poor free cutting behavior when usedin the core drill bit application.

Other copper-based infiltrants similar to Cu53 include

Cu: 86, Ni: 2, Mg: 12;

Cu: 80 Sn: 20;

Cu: 79.2, Ni: 10, Mg: 5; Sn: 5.5. Si: 0.3;

Cu: 70, Ni: 10, Mg: 20; and

Cu: 60 Zn: 40.

The above binder materials are not effective replacements for the moreexpensive Ag-containing binders due to poor properties, such as poorfree cutting behavior.

The most common core drill bit binder materials include Ag 40 (Cu 60; Ag40) Ag 30A (Cu: 70, Ag: 30) Ag 30B (Cu 60; Ni: 10 Ag; 30), Ag 20 (Cu 76;Ag 20; Ni 4) and Ag 10 (Cu: 90; Ag: 10) (with all alloying compositionsprovided in wt. %).

EP2771533B1 describes Ag-free binder alloys having Zn content of 25% ormore in copper and/or nickel binder alloys. Use of high Zn levels can beproblematic since Zn can easily vaporize in a variety of industrialmanufacturing operations, which can lead to health concerns and/orconsistency issues in product performance.

Despite the high cost of Ag, because Ag-free alloys exhibit decreasedperformance and/or have health/manufacturing issues, alloys comprising asignificant amount of Ag remain binder materials of choice for abrasiveapplications such as core drill bits.

There is a need for binder materials comprising decreased amounts of Ag,preferably Ag-free, that exhibit good properties in abrasiveapplications such as core drill bits. There is a need for high qualitycomponents for abrasive applications comprising binder materials withlow or no Ag content and/or low or no Zn content.

SUMMARY OF THE INVENTION

An alloy is provided comprising 1-33 wt % Ni, 12-38 wt % Sn, and Cu,wherein Cu is the plurality or majority component. Preferably, thebinder alloy comprises 10 wt % Ag or less, or 5 wt % Ag or less.Preferably, the binder alloy comprises 20 wt % Zn or less, or 5 wt % Znor less.

Preferably, the binder alloy satisfies at least one of the followingformulas:

17-33 wt % Ni,12-24 wt % Sn,  (A1)

4-8 wt % Ni,15-29 wt % Sn,  (A2)

7-13 wt % Ni,20-28 wt % Sn,  (A3)

1-3 wt % Ni,14-27 wt % Sn, or  (A4)

6-12 wt % Ni,11-21 wt % Sn.  (A5)

Preferably, the binder alloy comprises a balance of Cu.

The mushy zone is defined as the liquidus temperature minus the solidustemperature. Preferably, the binder alloy has a mushy zone of 150K orless. Preferably, the binder alloy comprises a matrix microstructurecomprising a CuSn gamma phase, wherein the CuSn gamma phase comprises0.1% to 70% of the matrix microstructure

An abrasive article is provided comprising an abrasive material in amatrix comprising the binder alloy. The abrasive article preferablycomprises a core drill bit.

A core drill bit is provided comprising an abrasive material in a matrixcomprising the binder alloy. The core drill bit preferably has a Vickershardness HV_(0.3) of 250 or greater. The core drill bit preferably has atransverse rupture strength (TRS) of 30 ksi (or 200 MPa) or greater. Asis known in the art, 1 ksi (kilopound/in²) is about 6.89 MPa.

A process of manufacturing a composite article, preferably an abrasivearticle, is provided, the process preferably comprising an infiltrationprocess. The process of manufacturing preferably comprises:

-   -   placing an abrasive particulate material into a mold;    -   melting a binder alloy (e.g., as described herein) to obtain a        molten binder;    -   allowing the molten binder to enter the mold and contact the        particulate material to obtain a coated particulate material;        and    -   cooling the coated particulate material to obtain the abrasive        article.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a CALPHAD diagram showing the mol fraction of various phasesof Cu 57 Ni 25 Sn 18 (wt %) as a function of temperature. Ni is notseparately shown since it is dissolved in the Cu FCC and CuSn gammaphase.

FIG. 2 is an SEM photomicrograph of a slice of Cu 57 Ni 25 Sn 18 (wt %)that has been melted and solidified.

FIG. 3 is a CALPHAD diagram showing the mol fraction of various phasesof Cu 61 Ni 10 Sn 29 (wt %) as a function of temperature. Ni is notseparately shown since it is dissolved in the Cu FCC and CuSn gammaphase.

FIG. 4 is an SEM photomicrograph of a slice of Cu 61 Ni 10 Sn 29 (wt %)that has been melted and solidified.

FIG. 5 is an SEM photomicrograph of a slice of Cu 57 Ni 25 Sn 18.

FIG. 6 is an SEM photomicrograph of a slice of Cu 61 Ni 10 Sn 29.

DESCRIPTION OF THE INVENTION

The present invention includes binder materials that comprise or consistof Ag-free or low-Ag binder alloys that can be used as binders forabrasive materials such as core drill bits. The alloys comprise, orconsist of, Cu, Sn and Ni, with Cu preferably the plurality or majoritycomponent. The present invention also includes methods of manufacturingabrasive materials comprising the binder alloys, such as infiltrationprocesses.

Binder Material:

A copper-based binder material is provided comprising a binder alloy,the binder alloy comprising copper as the plurality or majoritycomponent, and further comprising nickel and tin. The binder alloypreferably comprises 44-84 copper, 1-33 nickel, and 11-38 tin; morepreferably 51-81 copper, 1-29 nickel, and 13-34 tin. All amounts areprovided in wt %.

Some preferred binder alloys include (with copper the balance):

Ni:17-33,Sn:12-24 more preferably Ni:21-29,Sn:15-21;  A1:

Ni:4-8,Sn:15-29 more preferably Ni:5-7,Sn:18-25;  A2:

Ni:7-13,Sn:20-38 more preferably Ni:8-12,Sn:24-34;  A3:

Ni:1-3,Sn:14-27 more preferably Ni:1-3,Sn:17-24; and  A4:

Ni:6-12,Sn:11-21 more preferably Ni:7-11,Sn:13-19  A5:

It is desirable to limit Ag content as elevated levels of Ag increasesthe raw material cost of the binder alloy. While it is permissible toinclude silver, preferred binder alloys comprise less than 10 wt % Ag,preferably less than 5 wt %. Ag, below 1 wt % Ag, below 0.1 wt % Ag,below 0.01 wt % Ag, or 0 wt % Ag. Ranges including two of these valuesare also preferred. Some preferred ranges include 0-10 wt % Ag, 0-5 wt %Ag, 0-1 wt % Ag, 0-0.1 wt % Ag, 0-0.01 wt % Ag, 0.01-10 wt % Ag, 0.01-5wt % Ag, 0.01-1 wt % Ag, 0.01-0.1 wt % Ag, 0.1-10 wt % Ag, 0.1-5 wt %Ag, 0.1-1 wt % Ag, 1-10 wt % Ag, and 1-5 wt % Ag.

It is preferable to limit Zn content as Zn can easily vaporize in avariety of industrial manufacturing operations which can lead to healthconcerns and/or consistency issues in product performance. Preferably Zncontent in the binder alloy is below 20 wt %, below 10 wt %, below 1 wt%, below 0.1 wt % or 0 wt % Zn. Ranges including two of these values arealso preferred. Some preferred ranges include 0-20 wt % Zn, 0-10 wt %Zn, 0-1 wt %/o Zn, 1-0.1 wt % Zn, 0.1-20 wt % Zn, 0.1-10 wt % Zn, 0.1-1wt % Zn, 1-20 wt % Zn, and 1-10 wt % Zn.

Preferably, the binder alloy comprises, or consists of, Cu Ni and Sn.All such binder alloys permit the presence of trace impurities. Traceimpurities can include, e.g., O, S, P, Bi, Si, Al, and combinations ofone or more thereof. Trace impurities are preferably present in amountsof less than or equal to 1.0 wt %, 0.1 wt %, or 0.05 wt %, individuallyor collectively (i.e., two or more thereof). Some preferred amountsinclude 0-1.0 wt %, 0-0.1 wt %, 0-0.05 wt %, 0.05-1.0 wt %, 0.05-0.1 wt%, and 0.1-1.0 wt %, individually or collectively.

Thermodynamics:

The binder alloys disclosed herein can be described by thermodynamicfeatures.

The binder alloys described herein preferably exhibit eutectictransitions, whereby two different solid phases precipitate from theliquid upon cooling. This eutectic transition can create amicrostructure useful for free cutting behavior necessary for core drillbit performance.

One phase of the eutectic transition is preferably FCC copper. Anotherphase of the eutectic transition is preferably CuSn gamma phase. It hasbeen demonstrated via experimental efforts presented below that the CuSngamma phase fraction present at the solidus temperature in a CALPHADthermodynamic calculation closely resembles the experimentally measuredCuSn gamma phase fraction of an arc melted ingot. Thus, the CuSn gammaphase fraction calculated or determined at the solidus temperature canbe used as a parameter for alloy design.

In some embodiments the CuSn gamma phase fraction at solidus is 10 mol %or greater, 20 mol % or greater, or 30 mol % or greater.

It is also desirable for the infiltration binder alloys to have asufficiently low melting temperature such that they can be sufficientlyinfiltrated with conventional commercial processes. It is also generallydesirable for the mushy zone to be as low as possible which results in alower degree of compositional variation from the top of the drill bit tothe bottom. A smaller mushy zone can be obtained by providing alloyshaving proportions of components at the eutectic point or near theeutectic point (hypereutectic or hypoeutectic). For precise eutecticcompositions, e.g., alloys in which the composition corresponds to theminimum of the eutectic well, the liquidus and solidus merge, such thatthe mushy zone is OK.

In particular, the eutectic point can be characterized by thecomposition at which two solids precipitate from the liquid withouteither solid precipitating first at a higher temperature. A binary(e.g., two elements) eutectic system yields a mushy zone of OK. Inmulti-element systems it is possible to have two solids start toprecipitate at the same temperature from the liquid and to have anon-zero mushy zone (e.g., alloy X3 described below). In such cases theeutectic point corresponds to the minimum possible mushy zone which canbe achieved in the alloy system.

It is generally advantageous for the binder alloy to have a small mushyzone. Among other things, a small mushy zone results in more uniformarticles of manufacture, e.g., manufacture by an infiltration process.The mushy zone of the binder alloy is preferably 150K or lower, 110K orlower, 100K or lower, or 75K or lower. The mushy zone is generally OK orhigher, 10K or higher, or 20K or higher. Some preferred ranges include0-150K, 0-110K, 0-100K, 0-75K, 10-150K, 10-110K, 10-100K, 10-75K,20-150K, 20-110K, 20-100K, and 20-75K.

There is no precise upper limit on the liquidus of the binder alloy,though it should preferably be low enough to be amenable to manufacturean article by an infiltration process without damaging the particulatematerial in the particular application. As a general matter, theliquidus temperature of the binder alloy can be 1300K or lower, 1175K orlower, or 1150K or lower. There is no fixed lower limit on the liquidusof the binder alloy, though as a general matter the liquidus can be1050K or higher, or 1100K or higher. Some preferred ranges include1050-1300K, 1050-1175K, 1050-1150K, 1100-1300K, 1100-1175K, and1100-1150K.

Microstructure:

Binder alloys of the present invention can also be described in terms oftheir microstructural features. The binder alloys form a eutectic typemicrostructure comprising a copper matrix and a CuSn gamma phase (inwhich phases the Ni is dissolved). Specifically, the alloy may bepro-eutectic wherein the copper based matrix forms in advance of theCuSn gamma phase during solidification of the material.

Through alloy control it is possible to adjust the fraction of the CuSngamma phase and it is desirable to do so dependent on drillingconditions. Currently, such a processes have been done using varied Agcontents with increased Ag leading to increased precipitate phasefraction.

The CuSn gamma phase preferably comprises 0.1% or more, 5% or more, or20% a or more of the matrix microstructure. The CuSn gamma phasepreferably comprises 70% or less, 65% or less, or 60% or less of thematrix microstructure. Some preferred ranges for the CuSn gamma phaseinclude 0.1-70%, 0.1-65%, 0.1-60%, 5-70/o, 5-65%, 5-60%, 20-70%, 20-65%,and 20-60%, of the matrix microstructure. The FCC Cu phase preferablycomprises 70% or less, 65% or less, or 60% or less of the matrixmicrostructure. The FCC Cu phase preferably comprises 0.1% or more, 5%or more, or 20% or more of the matrix microstructure. Some preferredranges for the FCC Cu phase include 0.1-70%, 0.1-65%, 0.1-60%, 5-70%,5-65%, 5-60%, 20-70%, 20-65%, and 20-60% of the matrix microstructure.Phase proportions can be measured using image analysis (preferably usingimage analysis software) of SEM images to measure area fraction of agiven phase.

Abrasive Articles:

Abrasive articles according to the present invention include particulatematerial bound to a metal matrix, the metal matrix comprising,consisting essentially of, or consisting of, a binder alloy as describedherein. Abrasive articles preferably include drill bits, including coredrill bits.

An advantageous process for manufacturing abrasive articles, such ascore drill bits, is by infiltration. The particulate material cancomprise any particulate material suitable for use in an abrasivearticle, e.g., a core drill bit. The particulate material preferablydoes not undergo melting, and preferably does not undergo sintering, attemperatures used in the manufacturing process, such as infiltration.Some suitable particulate materials include refractory metals (e.g.,tungsten, molybdenum, and/or niobium) and/or other materials (e.g.,carbides (such as tungsten carbide and/or silicon carbide), graphiteand/or diamond).

Performance:

An effective core drill bit binder alloy should infiltrate a moldcomprising an abrasive particulate e.g., tungsten powder, at typicalindustry infiltration temperatures; exhibit good bonding with thetungsten particles to form a strong composite structure; and possess asufficiently high hardness value.

Methods to quantify the quality of infiltration and bonding inexperimental binder alloys include microstructural evaluation, andmeasurement of the transverse rupture strength of the composite part.

Any temperature suitable for the infiltration process may be used, andcan be determined by a person of ordinary skill in the art in view ofthe materials used, and using the present disclosure as a guide. Withoutlimiting the present disclosure, binding alloys disclosed herein exhibitgood infiltration and bonding with tungsten particles at 1200° C. orbelow, or at 1100° or below. The infiltration process should take placeat a temperature above the liquidus of the binding alloy.

In some embodiments, the alloys exhibit good infiltration and bondingwith tungsten particles as characterized by a TRS of 40 ksi (or 275 MPa)or greater in a tungsten matrix infiltrated pin. In preferredembodiments, the alloys exhibit good infiltration and bonding withtungsten particles as characterized by a TRS of 75 ksi (or 515 MPa) orgreater in a tungsten matrix infiltrated pin. In still preferredembodiments, the alloys exhibit good infiltration and bonding withtungsten particles as characterized by a TRS of 90 ksi (or 620 MPa) orgreater in a tungsten matrix infiltrated pin

Depending on drilling conditions, it may be desirable to tailor tohardness of the binder alloy to harder or softer sides of the spectrum.The Cu—Ni—Sn alloy space disclosed here offer a greater degree ofhardness tuneability. The Ag20 and Ag40 alloys are similar in hardnessat 100 HV Vicker hardness. In contrast, the X1 and X3 alloys have ˜300HV and the X2, X4 alloys have ˜200 HV.

In some embodiments, the alloys exhibit Vickers hardness in excess of100 HV. In preferred embodiments, the alloys exhibit Vickers hardness inexcess of 200 HV. In preferred embodiments, the alloys exhibit Vickershardness in excess of 300 HV. Some preferred ranges include 100-300 HV,100-100 HV, and 200-300 HV.

Abrasive articles comprising abrasive particles in a matrix comprisingthe binder alloy exhibit good properties such as hardness and strength.Vickers hardness HV_(0.3) is preferably greater than or equal to 250,300, or 350. While there is no preferred upper limit, as a practicalmatter, Vickers hardness will generally be less than or equal to 450 or400. The units for Vickers hardness is kgf/mm². Some preferred rangesinclude 250-450 kgf/mm², 250-400 kgf/mm², 300-450 kgf/mm², 300-400kgf/mm², 350-450 kgf/mm², and 350-400 kgf/mm².

The above abrasive articles exhibit high transverse rupture strength(TRS), e.g., as measured on infiltrated pins manufactured from the samecomposition (e.g., abrasive particles and binder alloy). The TRS ispreferably greater than or equal to 30 ksi (or 200 MPa), 50 ksi (or 345MPa), or 75 ksi (or 515 MPa). While there is no preferred upper limit,as a practical matter, TRS will generally be less than or equal to 200ksi (or 1375 MPa), 150 ksi (or 1030 MPa), or 125 ksi (or 860 MPa). Somepreferred TSR ranges include 30-200 ksi, 30-150 ksi, 30-124 ksi, 50-200ksi, 50-150 ksi, 50-124 ksi, 75-200 ksi, 75-150 ksi, 75-124 ksi,200-1375 MPa, 200-1030 MPa, 200-860 MPa, 345-1375 MPa, 345-1030 MPa,345-860 MPa, 515-1375 MPa, 515-1030 MPa, and 515-860 MPa.

Examples

Four Example binding alloys were prepared, having the following nominalcompositions (in wt %):

Cu57Ni25Sn18  X1:

Cu72Ni6Sn22  X2:

Cu61Ni10Sn29  X3:

Cu77Ni2Sn21  X4:

Two Comparative Examples were also prepared, Ag20 (Cu 76 Ag 20 Ni 4) andAg40 (Cu 60 Ag40).

The four experimental alloys (X1, X2, X3, and X4) and two ComparativeExamples were manufactured into ingots for experimentalcharacterization. This included microstructure analysis to determinephase fractions and phase compositions, and alloy hardness. The measuredCuSn gamma phase fraction and hardness values for the manufacturedingots prior to infiltration are shown in Table 1. Hardness (HV_(0.2))was measured using the Vickers hardness test with an applied load of 0.2kgf and a loading time of 15 seconds.

TABLE 1 Experimental Ingot Results AgCu γ Phase CuSn γ Phase HardnessIngot Fraction Fraction (HV_(0.2)) X1 18% 313 X2 31% 224 X3 52% 293 X427% 196 Ag20 13% 105 Ag40 37% 109

The four experimental alloys were then infiltrated into a tungstenmatrix powder to simulate industrial core drill bit manufacturingconditions, and evaluated. The procedure utilized a graphite mold tocast 12.7 mm diameter×˜100 mm long pins. The molds were first filledwith fine tungsten powder. The tungsten powder was then pressed with anapplied load of 350 lbs to achieve a pressing pressure of 1783 psi.Next, the copper binder alloy and a mixture of flux was place into themold cavity above the tungsten powder. The mold was then place into afurnace at 1100° C. to melt the binder alloy. Once molten, gravitycauses the copper alloy to flow into the tungsten powder forming a solidinfiltrated pin. The hardness and transvers rupture strength (TRS) ofeach pin was then characterized as follows.

Transverse rupture strength (TRS) was measured using a three-point bendtest method with a span of 2 inches on test coupons formed as above,i.e., in the form of 0.5 inch (12.7 mm) diameter pins, approximately 4inches (100 mm) in length. The applied load rate was 80 lbs/sec. The TRSvalue a is calculated from the following equation:

$\sigma = \frac{FL}{\pi R^{3}}$

where σ is stress (psi); F is load (lbf); L is span (in); and R is pinradius (in).

Hardness (HV_(0.3)) was measured using the Vickers hardness test with anapplied load of 0.3 kgf and a loading time of 15 seconds. The average ofsix hardness measurements was used to quantify the hardness of eachinfiltrated pin. Results are shown in Table 2.

TABLE 2 Experimental Results for Infiltrated Pins Pin Pin PinInfiltrated Hardness at Hardness at Density TRS TRS Pin Top (HV_(0.3))Bottom (HV_(0.3)) (g/cm³) (ksi) (MPa) X1 388 380 13.42 103.1 710.4 X2339 290 13.23 87.2 600.8 X3 396 395 13.46 40.9 281.8 X4 298 303 13.1386.4 595.3 Ag20 214 158 13.53 95.1 655.2 Ag40 204 195 13.54 125.5 864.7

Binder alloy X1 exhibited a transverse rupture strength (TRS) of 103 ksi(or 710 MPa) and the X3 alloy exhibited a TRS of 41 ksi (or 282 MPa). Incomparison the Ag20 core binder alloy run under similar infiltrationconditions had a TRS of 95 ksi (or 655 MPa).

Binder alloy X1 is an example of a pro-eutectic alloy. FIG. 1 shows thethermodynamic behavior of X1 wherein the FCC Cu matrix 101, is presentat a higher temperature and thus forms in advance of the CuSn gammaphase 102 during solidification. FIG. 2 shows the microstructure ofsolidified binder alloy X1 comprising primarily FCC Copper 201 with CuSngamma phase precipitates 202.

As seen in FIG. 1 , binder alloy X1 has a CuSn gamma phase fraction atsolidus of about 25 mol %. X1 has a liquidus of 1290K and a solidus of1165K resulting in a 125K mushy zone.

In the low-Ag (including Ag-free) binder alloys disclosed herein, thebinder alloy can be designed to form a perfect eutectic, alloy X3, suchas shown in FIG. 3 and FIG. 4 . FIG. 3 shows how both the FCC Cu matrixphase 301 and the CuSn gamma phase 302 form at the same temperature. Themicrostructure of this alloy is shown in FIG. 4 showing Cu FCC phase 401and CuSn gamma phase 402. As noted, the CuSn gamma phase precipitatefraction 402 is significantly higher than in the pro-eutectic alloycase.

As seen in FIG. 3 , binder alloy X3 has a CuSn gamma phase fraction atsolidus of about 61 mol %. X3 has a liquidus of 1131K and a solidus of1075K resulting in a 56K mushy zone.

Scanning electron microscopy for alloys X1 and X3 are shown in FIG. 5and FIG. 6 respectively. Both micrographs shows tungsten particles, 502and 602 well bonded to the binder alloys 501, 601 (Cu-rich) and 603(Sn-rich).

The particulars shown herein are by way of example and for purposes ofillustrative discussion of the embodiments of the present invention onlyand are presented in the cause of providing what is believed to be themost useful and readily understood description of the principles andconceptual aspects of the present invention. In this regard, no attemptis made to show structural details of the present invention in moredetail than is necessary for the fundamental understanding of thepresent invention, the description taken with the drawings makingapparent to those skilled in the art how the several forms of thepresent invention may be embodied in practice.

The foregoing examples are provided merely for explanation, and are notto be construed as limiting the present invention. While the presentinvention has been described with reference to exemplary embodiments, itis understood that the words which have been used herein are words ofdescription and illustration, rather than words of limitation. Changesmay be made, within the purview of the appended claims, as presentlystated and as amended, without departing from the scope and spirit ofthe present invention in its aspects. Although the present invention hasbeen described herein with reference to particular means, materials andembodiments, the present invention is not intended to be limited to theparticulars disclosed herein; rather, the present invention extends toall functionally equivalent structures, methods and uses, such as arewithin the scope of the appended claims, as presently stated and asamended.

1. A binder alloy comprising 1-33 wt % Ni, 11-38 wt % Sn, and Cu,wherein Cu is the plurality or majority component, and wherein thebinder alloy comprises less than 10 wt % Ag, and less than 20 wt % Zn.2. The binder alloy of claim 1 satisfying at least one of the followingformulas:17-33 wt % Ni,12-24 wt % Sn,  (A1)4-8 wt % Ni,15-29 wt % Sn,  (A2)7-13 wt % Ni,20-28 wt % Sn,  (A3)1-3 wt % Ni,14-27 wt % Sn, or  (A4)6-12 wt % Ni,11-21 wt % Sn  (A5) comprising less than 5 wt % Ag, lessthan 5 wt % Zn, and a balance of Cu.
 3. An abrasive article comprisingan abrasive material in a matrix comprising the binder alloy of claim 1.4. An abrasive article comprising an abrasive material in a matrixcomprising the binder alloy of claim
 2. 5. The binder alloy of claim 2having a mushy zone of 150K or less.
 6. The binder alloy of claim 2,comprising a matrix microstructure comprising a CuSn gamma phase,wherein the CuSn gamma phase comprises 0.1% to 70% of the matrixmicrostructure
 7. The abrasive article of claim 3, wherein the abrasivearticle is a core drill bit.
 8. The drill core bit of claim 7 havingVickers hardness HV_(0.3) of 250 or greater.
 9. The drill core bit ofclaim 7 having TRS of 200 MPa or greater.
 10. A process formanufacturing an abrasive article comprising: placing an abrasiveparticulate material into a mold; melting a binder alloy according toclaim 1 to obtain a molten binder; allowing the molten binder to enterthe mold and contact the particulate material to obtain a coatedparticulate material; and cooling the coated particulate material toobtain the abrasive article.
 11. The binder alloy of claim 1 comprising17-33 wt % Ni and 12-24 wt % Sn.
 12. The binder alloy of claim 11comprising 17-33 wt % Ni, 12-24 wt % Sn, and the balance copper.
 13. Thebinder alloy of claim 1 comprising 21-29 wt % Ni and 15-21 wt % Sn. 14.The binder alloy claim 13 comprising 21-29 wt % Ni, 15-21 wt % Sn, andthe balance copper.
 15. A process for manufacturing an abrasive articlecomprising: placing an abrasive particulate material into a mold;melting a binder alloy according to claim 11 to obtain a molten binder;allowing the molten binder to enter the mold and contact the particulatematerial to obtain a coated particulate material; and cooling the coatedparticulate material to obtain the abrasive article.
 16. A process formanufacturing an abrasive article comprising: placing an abrasiveparticulate material into a mold; melting a binder alloy according toclaim 13 to obtain a molten binder; allowing the molten binder to enterthe mold and contact the particulate material to obtain a coatedparticulate material; and cooling the coated particulate material toobtain the abrasive article.